The invention concerns a remote security and operating system that communicates with a system user over standard telephone lines.
Various devices have been proposed for monitoring and controlling equipment from remote locations, such as the irrigation system discussed in U.S. Pat. No. 4,095,050 to Beachem et al. The irrigation system is dialed from a remote telephone and gives a status of system sensors to the user. After using a code, punched on a push-button telephone and verification of the code by the system, elements of the system may be started or stopped. The disadvantages of this system are explained in U.S. Pat. No. 4,493,947 to Loveless.
U.S. Pat. No. 4,493,947 to Loveless discusses a security device using conventional telephone lines. Sensor faults are determined and an automatic call-up circuit dials a selected telephone number to report sensor faults. A deceiver ring signal is generated whenever a remote telephone is used to dial the system, which ceases when a security code is entered. To change the selected telephone number, the device operator must travel to the security device and reset switches. The device is physically connected to telephone lines and requires two push-button telephones. An identification circuit uses different frequencies to indicate where separate devices are located, requiring a tone decoder at the operator's remote telephone. Also, the device has no provision for stopping the scanning of sensors once a call-up has been received by the device operator.
U.S. Pat. No. 4,371,751 to Hilligross, Jr. et al. deals with an automatic telephonic apparatus including a base station and a remote unit. The base station automatically dials a plurality of telephone numbers upon detecting emergency conditions, and them transmits an aural message. A 16 digit keyboard of the base station is pushed to input telephone numbers to be called. The base station receives emergency signals from local external alarms or the remote units which transmit RF signals to the base station in response to appropriate stimulation. The operator cannot dial the apparatus to check conditions, but must wait until the apparatus calls. No calls by the apparatus might indicate all conditions are acceptable, but could mean the apparatus is not working. The operator would never know.
U.S. Pat. No. 4,121,053 to Dick involves a telephone command apparatus with an access device responsive to decoded signals representing a correct sequence of two-tone signals. Subsequent two-tone signals condition an oscillator to generate audible signals of different frequency, indicating the on-off status of a selected operation.
Blouch's U.S. Pat. No. 3,829,616 shows a ringer blocking attachment for a telephone. A simulated ring is heard by a dialing party, while the called party hears nothing. The dialing party must enter a set code before the called party hears a ring.
U.S. Pat. No. 4,284,849 to Anderson et al. concerns a monitoring and signaling system. A remote unit regularly telephones a center and delivers data representing a count of times a sensor has monitored an activity and produced signals, or telephones anytime a signal is not received from a sensor within a set period.